Heat dissipation housing for led lamp

ABSTRACT

The present invention is to provide a heat dissipation housing for an LED lamp, which is made as a one-piece member by metal casting and formed with a receiving channel axially passing therethrough. A plurality of cooling fins axially are formed on an outer surface of the housing, wherein each said cooling fin is radially extended out of the housing and formed therein with a plurality of heat dissipation holes, and has two opposite sides with an included angle defined therebetween. Therefore, when an LED lamp installed on an end of the receiving channel starts to emit light, heat exchange between the LED lamp and the ambient cooling air outside the housing can be carried out through the cooling fins and the heat dissipation holes by both of thermal conduction and thermal convection, so as to effectively enhance the heat dissipation efficiency of the housing for the LED lamp.

FIELD OF THE INVENTION

The present invention relates to a housing for an LED lamp, more particularly to a heat dissipation housing for an LED lamp, of which an outer surface is axially formed with a plurality of cooling fins. Each of the cooling fins is radially extended out of the heat dissipation housing and formed with a plurality of heat dissipation holes therein for communicating the air inside and outside the heat dissipation housing, wherein each of the cooling fins has two opposite sides, and an included angle is defined between the two opposite sides. Thus, when an LED lamp is installed on the heat dissipation housing and starts to emit light, heat exchange between heat generated by the LED lamp and the ambient cooling air outside the heat dissipation housing can be carried out through the cooling fins and the heat dissipation holes by both of thermal conduction and thermal convection, so as to effectively enhance the heat dissipation efficiency of the housing for the LED lamp.

BACKGROUND OF THE INVENTION

Recently, with the development of technologies, demands for energies are gradually increased day by day. In the past, people use incandescent lamps for night or indoor illumination. However, the usage life of the incandescent lamps is relatively short (the average usage life there is only 1,000 hours). Traditionally, the incandescent lamp is provided with a tungsten filament received in a vacuum space or an inert gas space. When an electric current passes through the tungsten filament, the tungsten filament is heated to be incandescent, so as to generate light. However, the incandescent lamp only can convert about 10% of received electric energy into light energy, while about 90% of electric energy is converted into useless heat energy which is then dissipated into the ambient atmosphere. As a result, not only the electric energy is considerably wasted and consumed, but also the burden of the natural environment is heavier.

To solve the foregoing disadvantages of the incandescent lamp (such as the short usage life and low photoelectric conversion rate), a fluorescent lamp constructed by a fluorescent bulb and a ballast are developed to replace the incandescent lamp. Under the same illumination conditions, the usage life (about 6,000 hours) of the fluorescent lamp is six times as that of the incandescent lamp. Meanwhile, the power consumption of the fluorescent lamp is apparently lower than that of the incandescent lamp, wherein the power consumption of the fluorescent lamp is about one-fifth as that of the incandescent lamp. Therefore, in more than ten years ago, many people have started to use energy-saving fluorescent lamps. In addition, the size of the fluorescent lamp is similar to that of the incandescent lamp, wherein a holder interface (i.e. an electrode cap or head) of the fluorescent lamp is also the same as that of the incandescent lamp, so that the fluorescent lamp can be directly used to replace the incandescent lamp without changing the holder interface. Thus, the incandescent lamp is gradually replaced by the fluorescent lamp, so that the fluorescent lamp becomes the mainstream of illumination lamps. However, the fluorescent lamp is filled with harmful mercury vapor and phosphorus-based fluorescent paints, while the usage life of the fluorescent lamp is still relatively short (only 6,000 hours). In a case of frequently using a large number of fluorescent lamps, there will be many waste fluorescent lamps in a short time. Once the waste fluorescent lamps are casually discarded, the harmful mercury vapor and phosphorus-based fluorescent paints therein will be released to pollute the natural environment and harm the ecology.

As described above, in addition to the foregoing incandescent lamp and fluorescent lamp, with the development of illumination technologies, many lamp manufacturers start to develop and manufacture light emitting diode (LED) lamps for protection the environment and saving the energy. The usage life of the LED lamp (about 40,000 hours) is about forty times as that of the incandescent lamp, so that the power consumption of the LED lamp is apparently lower than that of the fluorescent lamp or the incandescent lamp under the same illumination condition, wherein the power consumption of the LED lamp is about one-tenth as that of the incandescent lamp, while the power consumption of the LED lamp is about one-half as that of the fluorescent lamp. Moreover, the LED lamp doesn't contain toxic substances (such as mercury, Hg), while the light emitted by the LED lamp almost has no problems of waste heat or irradiation (i.e. the light spectrum generated by the light source of the LED lamp almost doesn't include ultraviolet or infrared). In addition, the manufacturing technologies of LEDs are gradually complete, and the cost of the LEDs is lowered day by day. Therefore, the incandescent lamp and fluorescent lamp are gradually replaced by the LED lamp, so that the LED lamp becomes the mainstream of illumination lamps nowadays.

As described above, although the LED lamp becomes the mainstream of illumination lamps nowadays, LEDs still generate considerable heat while emitting light. Meanwhile, the higher the brightness of the LED is, the more waste heat the LED generates. Once the LED lamp having LEDs can not dissipate waste heat generated by the LEDs, the temperature of the LEDs will not be timely lowered down. If the LED lamp is continuously long-term used, it will cause serious material aging and luminous decay phenomenon, resulting in seriously shortening the usage life of the LED lamp. Therefore, to enhance the heat dissipation efficiency of the LED lamp to elongate the usage life thereof, manufacturers gradually develop various heat dissipation housings for the LED lamp. A traditional heat dissipation housing of an LED lamp is shown in FIG. 1 and described below.

Referring now to FIG. 1, a heat dissipation housing 10 is illustrated, wherein the heat dissipation housing 10 is made of aluminum alloy and is made as a one-piece member by metal casting. The heat dissipation housing 10 is formed with a receiving hole 101 passing therethrough for receiving a power printed circuit board (PCB) 11 and wires 111 thereon. An outer surface of the heat dissipation housing 10 is extended outward to form a plurality of cooling fins 102 which are adjacent to and spaced from each other. Each of the cooling fins 102 has two opposite sides parallel to each other, wherein each of the two opposite sides is vertically connected to the outer surface of the heat dissipation housing 10 by 90 degree. A first end of the heat dissipation housing 10 is used to carry an electrode cap 12, and a second end thereof is used to carry a light emitting module 13 which comprises at least one LED 131 and a base 132. A first side surface of the base 132 is mounted with the LED 131, and a second side surface thereof is attached to the second end of the heat dissipation housing 10. Therefore, when the electrode cap 12, the power PCB 11, the wires 111 and the light emitting module 13 are installed to the heat dissipation housing 10, the LED 131 on the light emitting module 13 is electrically connected to the power PCB 11 through the wires 111, so that an external electric power from the power PCB 11 and the electrode cap 12 can be supplied to the LED 131. Thus, the LED 131 can emit color light. Meanwhile, heat generated by the LED 131 is transmitted to the heat dissipation housing 10 through the second side surface of the base 132, and then dissipated to the ambient atmosphere through the heat dissipation housing 10 and the cooling fins 102 thereon. As a result, the operational temperature of the LED 131 can be lowered, so that the LED 131 can be kept to emit ideal color light.

However, because each of the two opposite sides of the cooling fins 102 is parallel to each other and each of the cooling fins 102 is vertically connected to the outer surface of the heat dissipation housing 10 by 90 degree, it causes that a dead space of air convection is formed between the adjacent cooling fins 102, wherein the air in the dead space between the adjacent cooling fins 102 absorbs the heat to raise the temperature of the air, and the high temperature air is accumulated around the cooling fins 102. As a result, the temperature difference between the cooling fins 102 and the ambient atmosphere is gradually narrowed, resulting in lowering the efficiency of air convection between the adjacent cooling fins 102. If heat transmitted from the LED 131 can not be efficiently dissipated, the operational temperature of the LED 131 can not be lowered, so that there is still problems of material aging and luminous decay phenomenon existing in the light emitting module 13 installed on the heat dissipation housing 10 to seriously shortening the usage life of the LED lamp.

As a result, it is important for related manufacturers to think how to improve the traditional heat dissipation housing of the LED lamp to prevent from forming a dead space of air convection between the adjacent cooling fins on the heat dissipation housing for enhancing the efficiency of air convection between the adjacent cooling fins, and to form heat dissipation holes on the cooling fins for increasing the heat dissipation surface of each cooling fins, so that heat exchange between the heat dissipation housing and the ambient atmosphere can be carried out by both of thermal conduction and thermal convection of the heat dissipation housing, for the purpose of substantially enhancing the efficiency of the heat dissipation housing.

It is therefore tried by the inventor to develop a heat dissipation housing of an LED lamp to solve the problems existing in the traditional heat dissipation housing as described above, so as to substantially enhance the efficiency of the heat dissipation housing and elongate the usage life of the LED lamp.

BRIEF SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a heat dissipation housing for an LED lamp, which is made as a one-piece member by metal casting, and formed with a receiving channel axially passing therethrough for receiving a power printed circuit board (PCB) and wires of the LED lamp. An outer surface of the heat dissipation housing is axially formed with a plurality of cooling fins. Each of the cooling fins is radially extended out of the heat dissipation housing, while the radial length of each of the cooling fins adjacent to a first end of the heat dissipation housing is smaller than that of each of the cooling fins adjacent to a second end of the heat dissipation housing. The first end of the heat dissipation housing is used to carry an electrode cap, while the second end thereof is used to carry a light emitting element of the LED lamp (such as a base with LED). Each of the cooling fins has two opposite sides, and an included angle is defined between the two opposite sides to prevent from forming a dead space of air convection between the adjacent cooling fins, so as to substantially enhancing the efficiency of air convection between the cooling fins. Each of the cooling fins is formed with a plurality of heat dissipation holes therein for communicating the air inside and outside the heat dissipation housing, wherein the heat dissipation holes can substantially increase the heat dissipation surface of each of the cooling fins, and a heat exchange between heat in each of the cooling fins and a cooling air outside each of the cooling fins can be carried out through the heat dissipation holes. Therefore, when the light emitting element is installed on a second end of the heat dissipation housing and starts to emit color light, heat exchange between heat generated by the light emitting element and the ambient cooling air outside the heat dissipation housing can be carried out through the cooling fins on the heat dissipation housing and the heat dissipation holes by both of thermal conduction and thermal convection. Meanwhile, the space between the cooling fins can provide the better air convection efficiency for rapidly dissipating heat on the surface of the cooling fins and heat in the heat dissipation holes to the ambient atmosphere. As a result, the temperature of the light emitting element can be rapidly lowered to a better operational temperature, so as to efficiently enhance the light emitting quality, the light emitting efficiency and the usage life of the light emitting element.

A secondary object of the present invention is to provide a heat dissipation housing for an LED lamp, wherein each portion of an inner surface of the heat dissipation housing corresponding to each of the cooling fins is formed with a recess along an axial direction of the heat dissipation housing, while the radial depth of each of the recesses adjacent to the first end of the heat dissipation housing is smaller than that of each of the recesses adjacent to the second end of the heat dissipation housing, wherein the recess is communicated with the heat dissipation holes. Therefore, the inner heat dissipation surface of each of the cooling fins can be substantially increased, so that heat generated by the LED on the second end of the heat dissipation housing can be rapidly transmitted to an outer surface of the cooling fins through the considerable heat dissipation surface provided by the recesses for carrying out a faster heat conduction effect. On the other hand, because each of the recesses is further formed with a larger heat convection space in the heat dissipation housing and each of the recesses is communicated with the receiving channel and the heat dissipation holes, the cooling air outside each of the cooling fins can easily enter each of the recesses and the receiving channel through the heat dissipation holes, while heat air inside the recesses and the receiving channel also can be smoothly dissipated out of the heat dissipation housing through the heat dissipation holes, for the purpose of carrying out a faster heat convection effect.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiment and the accompanying drawings, wherein

FIG. 1 is an exploded perspective view of a traditional LED lamp;

FIG. 2 is an exploded perspective view of a heat dissipation housing and other components of an LED lamp according to a preferred embodiment of the present invention;

FIG. 3 is a top view of the heat dissipation housing according to the preferred embodiment of the present invention; and

FIG. 4 is an enlarged perspective view of the heat dissipation housing according to the preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Generally, while a light emitting diode (LED) emits color light, the LED generates a large amount of heat. Thus, an LED lamp installed with LEDs is generally provided with a heat dissipation housing to dissipate heat generated by the LEDs to the ambient environment. Typically, the manufacturing methods of the heat dissipation housing can be classified into metal extrusion and metal casting. For a heat dissipation housing manufactured by metal extrusion, a pure metal plate (such as an aluminum plate) is extruded to integrate into one piece, so as to form the heat dissipation housing. However, the heat dissipation housing manufactured by metal extrusion has a rougher surface, so that the rougher surface must be finished by a secondary processing. It causes that the processing procedures are complicated and cost more time and manpower of manufacturers, so that the manufacture cost of the heat dissipation housing will be increased and the market competitiveness of the manufacturers will be lowered down. To solve the forgoing problems about metal extrusion, the technology of metal casing is developed. For a heat dissipation housing manufactured by metal casting, a metal alloy (such as aluminum alloy) is melted and cast to form a one-piece member, namely the heat dissipation housing. Generally, the price of the metal alloy material is lower than that of the pure metal plate, while the heat dissipation housing manufactured by metal casting has a finer surface without implementing a secondary processing. Thus, the price and cost of the heat dissipation housing manufactured by metal casting are apparently lower than that of the heat dissipation housing manufactured by metal extrusion. As a result, it is advantageous for the manufacturers to carry out the mass production of the heat dissipation housings. For this reason, metal casting gradually becomes the mainstream of manufacturing methods of the heat dissipation housings.

The present invention is related to a heat dissipation housing for an LED lamp. Referring now to FIG. 2, a heat dissipation housing for an LED lamp according to a preferred embodiment of the present invention is illustrated. As shown, the heat dissipation housing designated by numeral 20 is made of aluminum alloy material, and formed as a one-piece member by metal casting. However, the heat dissipation housing 20 also can be made of copper or other metal material in other embodiments of the present invention. The heat dissipation housing 20 is formed with a receiving channel 21 axially passing therethrough for receiving a power printed circuit board (PCB) 23 and wires 231 thereon. An outer surface of the heat dissipation housing 20 is axially formed with a plurality of cooling fins 24. Each of the cooling fins 24 is radially extended out of the heat dissipation housing 20, while the radial length of each of the cooling fins 24 adjacent to a first end of the heat dissipation housing 20 is smaller than that of each of the cooling fins 24 adjacent to a second end of the heat dissipation housing 20. The first end of the heat dissipation housing 20 is used to carry an electrode cap 25, while the second end thereof is used to carry a light emitting element 26 of an LED lamp 22. In the embodiment, the light emitting element 26 comprises at least one LED 261 and a base 262, wherein the base 262 has a first side surface for mounting the LED 261 and a second side surface attached to an upper surface of the second end of the heat dissipation housing 20. Meanwhile, the upper surface of the second end of the heat dissipation housing 20 is formed with a plurality of first connection holes 27 (such as those of screw connection), and the base 262 is formed with a plurality of second connection holes 28 corresponding to the first connection holes 27, so that a plurality of screws 29 can pass through the second connection holes 28 to be screw-connected to the first connection holes 27, respectively. Thus, the base 262 can be positioned on the upper surface of the second end of the heat dissipation housing 20. In addition, the width of a base of each of the cooling fins 24 (which refers to the position of the cooling fin 24 adjoined to the heat dissipation housing 20) is greater than that of one end of each of the cooling fins 24 away from the base, so that a first included angle is defined between the two opposite sides 242, 243 of each of the cooling fins 24, wherein the first included angle is preferably between 10 degree and 30 degree. Referring now to FIG. 3, a top view of the preferred embodiment of the present invention is illustrated. In the embodiment, the first included angle is 16 degree. Thus, corresponding edges of the bases of any two adjacent cooling fins 24 are adjoined to each other, while a second included angle is defined between the corresponding sides of the two adjacent cooling fins 24. Referring to FIG. 3, in the embodiment, the second included angle is of 34 degrees. As a result, it can prevent from forming a dead space of air convection between the adjacent cooling fins 24, so as to substantially enhance the efficiency of air convection between the cooling fins 24. In comparison, for the heat dissipation housing of the traditional LED lamp, two opposite sides of each of the cooling fins are parallel to each other, and each of the cooling fins is vertically connected to the outer surface of the heat dissipation housing by 90 degree, so that a dead space of air convection is formed between the adjacent cooling fins and the air convection from the hot air in the dead space between the adjacent cooling fins to the ambient cooling air can not be carried out, and thus the hot air is accumulated around the cooling fins, resulting in lowering the efficiency of air convection.

As described above, referring back to FIGS. 2 and 3, in the preferred embodiment, for increasing the heat dissipation surface, each of the cooling fins 24 has an inner surface formed with a plurality of heat dissipation holes 241, wherein the heat dissipation holes 241 can substantially increase the heat dissipation surface of each of the cooling fins 24, and axis of the heat dissipation hole 241 is parallel to axis of the receiving channel 21. Thus, heat generated by the LED 261 on the second end of the heat dissipation housing 20 can be rapidly transmitted to the outer surface of the cooling fins 24 through the larger heat dissipation surface provided by the heat dissipation holes 241, so that the heat exchange between the foregoing heat and the ambient cooling fins outside each of the cooling fins 24 can be carried out for providing the faster heat conduction effect. In addition, the heat dissipation holes 241 can be used to form a heat convection space in the cooling fins 24, while the heat dissipation holes 241 is communicated with the receiving channel 21. Thus, the cooling air outside each of the cooling fins 24 can easily enter the receiving channel 21 through the heat dissipation holes 241, while heat air inside the receiving channel 21 also can be smoothly dissipated out of the heat dissipation housing 20 through the heat dissipation holes 241, for the purpose of carrying out a faster heat convection effect.

Therefore, in assembly, the electrode cap 25, the power PCB 23 and the wires 231 are installed to corresponding positions of the heat dissipation housing 20, and the light emitting element 26 is installed to the second end of the heat dissipation housing 20. Then, the LED 261 on the light emitting element 26 is electrically connected to the power PCB 23 through the wires 231, so that the light emitting element 26 can obtain an external electric power from the power PCB 23 and the electrode cap 25 and then the electric power can be supplied to the LED 261. When the light emitting element 26 is switched on and the LED 261 thereon starts to emit color light, heat generated by the LED 261 can be transmitted to the heat dissipation housing 20 through the second side surface of the base 262, and then heat exchange between the foregoing heat and the ambient cooling air outside the heat dissipation housing 20 can be carried out through the cooling fins 24 on the heat dissipation housing 20 and the heat dissipation holes 241 by both of thermal conduction and thermal convection, respectively. Meanwhile, the space between the cooling fins 24 can provide the better air convection efficiency for rapidly dissipating heat on the surface of the cooling fins 24 and heat in the heat dissipation holes 241 to the ambient atmosphere. As a result, the temperature of the light emitting element 26 can be rapidly lowered to a better operational temperature, so as to efficiently enhance the light emitting quality, the light emitting efficiency and the usage life of the light emitting element 26.

As described above, referring now to FIGS. 2 and 4, each portion of an inner surface of the heat dissipation housing 20 corresponding to each of the cooling fins 24 is axially formed with a recess 201 along an axial direction of the heat dissipation housing 20, while the radial depth of each of the recess 201 adjacent to the first end of the heat dissipation housing 20 is smaller than that of each of the recess 201 adjacent to the second end of the heat dissipation housing 20, wherein the recess 201 is communicated with the heat dissipation holes 241. Therefore, the inner heat dissipation surface of each of the cooling fins 24 can be substantially increased, so that heat generated by the LED 261 on the second end of the heat dissipation housing 20 can be rapidly transmitted to an outer surface of the cooling fins 24 through the considerable heat dissipation surface provided by the recesses 201 for carrying out the heat exchange between the foregoing heat and the cooling air outside each of the cooling fins 24 to provide a faster heat conduction effect. On the other hand, because each of the recesses 201 is further formed with a larger heat convection space in the heat dissipation housing 20 and each of the recesses 201 is communicated with the receiving channel 21 and the heat dissipation holes 241, the cooling air outside each of the cooling fins 24 can easily enter each of the recesses 201 and the receiving channel 21 through the heat dissipation holes 241, while heat air inside the recesses 201 and the receiving channel 21 also can be smoothly dissipated out of the heat dissipation housing 20 through the heat dissipation holes 241, for the purpose of carrying out a faster heat convection effect. As a result, the recesses 201 and the heat dissipation holes 241 not only can substantially increase the heat dissipation surface of each of the cooling fins 24, but also a faster heat convection between hot air in each of the recesses 201 and cooling air outside each of the cooling fins 24 can be carried out through the heat dissipation holes 241, so that the air convection efficiency between the cooling fins 24 can be substantially enhanced.

As described above, the terms and descriptions thereof in the foregoing embodiment (such as the profile of the cooling fins and the connection manner between the light emitting element and the heat dissipation housing) are only one preferred embodiment of the present invention, but the present invention is not limited thereto.

The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications to the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

1. A heat dissipation housing for an LED lamp, the heat dissipation housing being formed as a one-piece member by metal casting and comprising: a receiving channel axially passing through the heat dissipation housing; a plurality of cooling fins axially formed on an outer surface of the heat dissipation housing, wherein each said cooling fin is radially extended out of the heat dissipation housing and formed therein with a plurality of heat dissipation holes, and axis of the heat dissipation hole is parallel to axis of the receiving channel; and a plurality of recesses being provided on an inner surface of the heat dissipation housing, each said recess corresponding to one said cooling fin and extending along an axial direction of the heat dissipation housing.
 2. The heat dissipation housing according to claim 1, wherein a first included angle is defined between two opposite sides of each said cooling fin.
 3. The heat dissipation housing according to claim 2, wherein a radial length of each said cooling fin adjacent to a first end of the heat dissipation housing is smaller than that of each said cooling fin adjacent to a second end of the heat dissipation housing.
 4. The heat dissipation housing according to claim 3, wherein a radial depth of each said recess adjacent to the first end of the heat dissipation housing is smaller than that of each said recess adjacent to the second end of the heat dissipation housing, wherein each said recess is communicated with the heat dissipation holes.
 5. The heat dissipation housing according to claim 4, wherein an upper surface of the second end of the heat dissipation housing is formed with at least one screw-connection hole. 